Prevention of acute kidney injury by low intensity pulsed ultrasound via anti-inflammation and anti-apoptosis

Alleviation of ischemia-reperfusion induced renal injury by chemically modified SOD2 mRNA delivered via lipid nanoparticles

Ischemia-reperfusion injury (IRI) is a major cause of acute kidney injury, which is a serious clinical condition with no effective pharmacological treatment. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) significantly alleviate kidney IRI; however, the underlying mechanisms and key molecules conferring renoprotection remain elusive. In this study, we characterized the protein composition of MSC-EVs using a proteomics approach and found that mitochondrial protein superoxide dismutase 2 (SOD2) was enriched in MSC-EVs. Using lipid nanoparticles (LNP), we successfully delivered chemically modified SOD2 mRNA into kidney cells and mice with kidney IRI. We demonstrated that SOD2 mRNA-LNP treatment decreased cellular reactive oxygen species (ROS) in cultured cells and ameliorated renal damage in IRI mice, as indicated by reduced levels of serum creatinine and restored tissue integrity compared with the control mRNA-LNP-injected group. Thus, the modulation of mitochondrial ROS levels through SOD2 upregulation by SOD2 mRNA-LNP delivery could be a novel therapeutic method for ischemia-reperfusion-induced acute kidney injury.

Low intensity pulsed ultrasound ameliorates Adriamycin-induced chronic renal injury by inhibiting ferroptosis

OBJECTIVE

It is very important to develop a new therapeutic strategy to cope with the increasing morbidity and mortality of chronic kidney disease (CKD). As a kind of physical therapy, low intensity pulsed ultrasound (LIPUS) has remarkable anti-inflammatory and repair-promoting effects and is expected to become a new therapeutic method for CKD. This study aims to clarify the treatment effect of LIPUS on CKD-related renal inflammation and fibrosis, and to further explore the potential signal network of LIPUS treatment for ameliorating chronic renal injury.

METHODS

A rat model simulating the progress of CKD was established by twice tail-vein injection of Adriamycin (ADR). Under anesthesia, bilateral kidneys of CKD rats were continuously stimulated by LIPUS for four weeks. The parameters of LIPUS were 1.0 MHz, 60 mW/cm2, 50% duty cycle and 20 min/d.

RESULTS

LIPUS treatment effectively inhibited ADR-induced renal inflammation and fibrosis, and improved CKD-related to oxidative stress and ferroptosis. In addition, the therapeutic effect of LIPUS is closely related to the regulation of TGF-β1/Smad and Nrf2/keap1/HO-1 signalling pathways.

DISCUSSION

This study provides a new direction for further mechanism research and lays an important foundation for clinical trials.

[Inhibitory effect of low-intensity pulsed ultrasound on apoptosis of splenic lymphocytes in septic rats]

OBJECTIVE

To investigate the inhibitory effect of low- intensity pulsed ultrasound (LIPUS) on apoptosis of splenic lymphocytes in rats with sepsis and explore its possible mechanism.

METHODS

Seventy-eight female SD rats were randomly divided into LIPUS group, cecal ligation and puncture (CLP) group and sham-operated group (Sham) (n=26), and in the former two groups, rat model of sepsis were established by CLP. Immediately after the operation, the rats in LIPUS group received pulsed ultrasound therapy with an ultrasound intensity of 200 mW/cm2, irradiation time of 20 min, and frequency of 0.37 MHz. The survival of the rats in each group was observed within 72 h after CLP. The changes in splenic lymphocyte counts were observed using HE staining, and apoptosis of the splenic lymphocytes was detected using TUNEL assay and flow cytometry. The expression levels of Bcl-2, Bcl2-associated X protein (Bax) and caspase-3 were detected by immunohistochemistry, Western blotting and RT-qPCR.

RESULTS

All the rats in the sham-operated group survived for over 72 h. The survival rates of the rats was significantly higher in LIPUS group than in CLP group (P<0.05). Compared with those in CLP group, the apoptosis rate of the splenic lymphocytes in LIPUS group was significantly decreased (P<0.05), the protein and mRNA expression levels of Bcl-2 were increased (P<0.05), and the protein and mRNA expression levels of Bax and caspase-3 were decreased (P<0.05).

CONCLUSIONS

LIPUS inhibits apoptosis of splenic lymphocytes in septic SD rats possibly by regulating the key molecules in the mitochondrial pathway, thereby improving the survival rate and prolonging the survival time of the rats.

NHWD-870 protects the kidney from ischemia/reperfusion injury by upregulating the PI3K/AKT signaling pathway (experimental study)

Renal ischemia-reperfusion injury is a critical clinical condition with a potentially fatal prognosis if not adequately managed. NHWD-870, a known Brd4 inhibitor with anti-cancer properties, exhibits additional attributes such as antioxidant, anti-inflammatory, and anti-apoptotic effects, suggesting its potential to preserve renal tissue and mitigate damage during ischemic insults. We aimed to assess the potential nephroprotective effect of NHWD-870 by investigating its anti-apoptotic, anti-inflammatory, and antioxidant properties in a rat model of renal ischemia-reperfusion injury. Male Wistar Albino rats (n=24) were randomly assigned to four groups: sham, control, vehicle, and NHWD-870. The control group experienced bilateral renal ischemia for 30 minutes, followed by 2 hours of reperfusion, while the sham group underwent a laparotomy without ischemia-reperfusion induction. The vehicle group received a DMSO injection, and the NHWD-870 group was administered 3mg/kg NHWD-870 orally 24 hours before repeating the control group protocol. Blood samples were collected after reperfusion for blood urea nitrogen (BUN) and serum creatinine (SCr) analysis. ELISA method was used to assess IL-1B, BCL-2, PGF-2, and PI3K/AKT signaling pathways in renal tissue. Tubular injury severity was evaluated through histopathological analysis. NHWD-870 treatment improved renal function and histological preservation compared to the control and vehicle groups. BUN, sCR, IL-1B, BCL-2, and PGF-2 levels in renal tissue were significantly improved in the NHWD-870 group (p<0.05). Furthermore, the PI3K/AKT signaling pathway was significantly upregulated (p<0.01), and tubular injury severity was reduced in the NHWD-870 group. NHWD-870 demonstrated substantial nephroprotective effects in reducing renal damage induced by ischemia-reperfusion injury in rats. These effects may be attributed to the anti-apoptotic properties, as indicated by increased levels of the anti-apoptotic protein Bcl-2, and the reduction in oxidative stress marker PGF-2 through upregulation of the PI3K/AKT signaling pathway, along with the decrease in the inflammatory marker IL-1B.

Preventing ischemia-reperfusion injury by acousto-mechanical local oxygen delivery

Ischemia-reperfusion (I/R) injury is a pathological process that causes vascular damage and dysfunction which increases recurrence and/or mortality in myocardial infarction, ischemic stroke, and organ transplantation. We hypothesized that ultrasound-stimulated oxygen-loaded microbubble (O₂-MB) cavitation would enhance mechanical force on endothelium and simultaneously release oxygen locally at the targeted vessels. This cooperation between biomechanical and biochemical stimuli might modulate endothelial metabolism, providing a potential clinical approach to the prevention of I/R injury. Murine hindlimb and cardiac I/R models were used to demonstrate the feasibility of injury prevention by O₂-MB cavitation. Increased mechanical force on endothelium induced eNOS-activated vasodilation and angiogenesis to prevent re-occlusion at the I/R vessels. Local oxygen therapy increased endothelial oxygenation that inhibited HIF-1α expression, increased ATP generation, and activated cyclin D1 for cell repair. Moreover, a decrease in interstitial H₂O₂ level reduced the expression of caspase3, NFκB, TNFα, and IL6, thus ameliorating inflammatory responses. O₂-MB cavitation showed efficacy in maintaining cardiac function and preventing myocardial fibrosis after I/R. Finally, we present a potential pathway for the modulation of endothelial metabolism by O₂-MB cavitation in relation to I/R injury, wound healing, and vascular bioeffects.

Dioscin Protects against Cisplatin-Induced Acute Kidney Injury by Reducing Ferroptosis and Apoptosis through Activating Nrf2/HO-1 Signaling

Acute kidney injury (AKI) is a clinical syndrome with high morbidity and mortality worldwide, and there is currently no effective means to prevent it. Dioscin is naturally present in the dioscoreaceae plants and has antioxidant and anti-inflammatory effects. Here, we found that dioscin is protective against cisplatin-induced AKI. Pathological and ultrastructural observations revealed that dioscin reduced renal tissue lesions and mitochondrial damage. Furthermore, dioscin markedly suppressed reactive oxygen species and malondialdehyde levels in the kidneys of AKI rats and increased the contents of glutathione and catalase. In addition, dioscin dramatically reduced the number of apoptotic cells and the expression of pro-apoptotic proteins in rat kidneys and human renal tubular epithelial cells (HK2). Conversely, the protein levels of anti-ferroptosis including GPX4 and FSP1 in vivo and in vitro were significantly enhanced after dioscin treatment. Mechanistically, dioscin promotes the entry of Nrf2 into the nucleus and regulates the expression of downstream HO-1 to exert renal protection. However, the nephroprotective effect of dioscin was weakened after inhibiting Nrf2 in vitro and in vivo. In conclusion, dioscin exerts a reno-protective effect by decreasing renal oxidative injury, apoptosis and ferroptosis through the Nrf2/HO-1 signaling pathway, providing a new insight into AKI prevention.

Therapeutic Ultrasound Halts Progression of Chronic Kidney Disease In Vivo via the Regulation of Markers Associated with Renal Epithelial-Mesenchymal Transition and Senescence

Low-intensity pulsed ultrasound (LIPUS), a therapeutic type of ultrasound, is known to enhance bone fracture repair processes and help some tissues to heal. Here, we investigated the therapeutic potential of LIPUS for the treatment of chronic kidney disease (CKD) in two CKD mouse models. CKD mice were induced using both unilateral renal ischemia/reperfusion injury (IRI) with nephrectomy and adenine administration. The left kidneys of the CKD mice were treated using LIPUS with the parameters of 3 MHz, 100 mW/cm2, and 20 min/day, based on the preliminary experiments. The mice were euthanized 14 days after IRI or 28 days after the end of adenine administration. LIPUS treatment effectively alleviated the decreases in the body weight and albumin/globulin ratio and the increases in the serum renal functional markers, fibroblast growth factor-23, renal pathological changes, and renal fibrosis in the CKD mice. The parameters for epithelial-mesenchymal transition (EMT), senescence-related signal induction, and the inhibition of α-Klotho and endogenous antioxidant enzyme protein expression in the kidneys of the CKD mice were also significantly alleviated by LIPUS. These results suggest that LIPUS treatment reduces CKD progression through the inhibition of EMT and senescence-related signals. The application of LIPUS may be an alternative non-invasive therapeutic intervention for CKD therapy.

NEPHROPROTECTIVE EFFECT OF OLMESARTAN ON RENAL ISCHEMIA REPERFUSION INJURY IN MALE RATS: THE ROLE OF NRF2/HO-1 SIGNALING PATHWAY

OBJECTIVE

The aim: To investigate the Nephroprotective potential of Olmesartan in RIRI via modulation of the Nrf2/OH-1 signaling pathway.

PATIENTS AND METHODS

Materials and methods: Thirty male rats were equally divided into four groups. The sham group was exposed to surgical conditions without induction of RIRI. The control group was exposed to ischemia by clamping the renal pedicles for 30 min, followed by 2h of blood restoration. The vehicle-treated group was received dimethyl sulfoxide (DMSO) by intraperitoneal injection (IP) 30 min before clamping.

RESULTS

Results: Olmesartan-treated group was pretreated with Olmesartan a dose of 10 mg/kg IP; 30 min prior to induction of ischemia. Following 30 min of ischemia, the clamps were released and allowed to the reperfusion for 2 h. Blood samples were collected to examine the levels of serum urea and creatinine. Kidney tissue was used to measure the levels of cytokines (TNFα, IL6, MCP, BAX, BCL2 and isoprostane F2. Immunohistochemistry was used to assess the levels of Nrf2 and HO-1. Histological analyses were used to detect the tubular damage in the kidney.

CONCLUSION

Conclusions: The results showed that Olmesartan alleviates renal tissue damage through activating the antioxidant effect mediated by Nrf2 signaling.

Nrf2-mediated anti-inflammatory polarization of macrophages as therapeutic targets for osteoarthritis

Macrophages are the most abundant immune cells within the synovial joints, and also the main innate immune effector cells triggering the initial inflammatory responses in the pathological process of osteoarthritis (OA). The transition of synovial macrophages between pro-inflammatory and anti-inflammatory phenotypes can play a key role in building the intra-articular microenvironment. The pro-inflammatory cascade induced by TNF-α, IL-1β, and IL-6 is closely related to M1 macrophages, resulting in the production of pro-chondrolytic mediators. However, IL-10, IL1RA, CCL-18, IGF, and TGF are closely related to M2 macrophages, leading to the protection of cartilage and the promoted regeneration. The inhibition of NF-κB signaling pathway is central in OA treatment via controlling inflammatory responses in macrophages, while the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway appears not to attract widespread attention in the field. Nrf2 is a transcription factor encoding a large number of antioxidant enzymes. The activation of Nrf2 can have antioxidant and anti-inflammatory effects, which can also have complex crosstalk with NF-κB signaling pathway. The activation of Nrf2 can inhibit the M1 polarization and promote the M2 polarization through potential signaling transductions including TGF-β/SMAD, TLR/NF-κB, and JAK/STAT signaling pathways, with the regulation or cooperation of Notch, NLRP3, PI3K/Akt, and MAPK signaling. And the expression of heme oxygenase-1 (HO-1) and the negative regulation of Nrf2 for NF-κB can be the main mechanisms for promotion. Furthermore, the candidates of OA treatment by activating Nrf2 to promote M2 phenotype macrophages in OA are also reviewed in this work, such as itaconate and fumarate derivatives, curcumin, quercetin, melatonin, mesenchymal stem cells, and low-intensity pulsed ultrasound.

LIPUS inhibits inflammation and catabolism through the NF-κB pathway in human degenerative nucleus pulposus cells

Background

Low-intensity pulsed ultrasound (LIPUS) is a safe and noninvasive rehabilitative physical therapy with anti-inflammatory effects. The current study investigated the effect of LIPUS on the inflammation of nucleus pulposus (NP) cells and its underlying mechanism.

Methods

Human NP cells were acquired from lumbar disc herniation tissue samples and cultured for experiments. Human NP cells were treated with LPS and then exposed to LIPUS (15 mW/cm², 30 mW/cm² and 60 mW/cm²) for 20 min daily for 3 days to determine the appropriate intensity to inhibit the expression of the inflammatory factors TNF-α and IL-1β. The gene and protein expression of aggrecan, collagen II, MMP-3 and MMP-9 was measured by real‐time PCR and western blotting, respectively. The activity of the nuclear factor‐kappa B (NF‐κB) pathway was examined by western blotting and immunofluorescence. After pretreatment with the NF-κB inhibitor PDTC, the expression of TNF-α, IL-1β, MMP-3 and MMP-9 was measured by real‐time PCR.

Results

LIPUS at intensities of 15 mW/cm², 30 mW/cm² and 60 mW/cm² inhibited LPS-induced NP cell expression of the inflammatory factors TNF-α and IL-1β, especially at 30 mW/cm². LIPUS significantly upregulated the gene and protein expression of aggrecan and collagen II and downregulated the gene and protein expression of MMP-3 and MMP-9 in LPS-induced NP cells. The NF‐κB signaling pathway was inhibited by LIPUS through inhibiting the protein expression of p-P65 and the translocation of P65 into the nucleus in LPS-induced NP cells. In addition, LIPUS had similar effects as the NF-κB inhibitor PDTC by inhibiting the NF-κB signaling pathway, inflammation and catabolism in LPS-induced human degenerative nucleus pulposus cells.

Conclusion

LIPUS inhibited inflammation and catabolism through the NF‐κB pathway in human degenerative nucleus pulposus cells.

Low-Intensity Pulsed Ultrasound Effect on MIO-M1 Cell Viability: Setup Validation and Standing Waves Analysis

Low-intensity pulsed ultrasound (LIPUS) has been proposed for novel therapies still under study, where similar parameters and protocols have been used for producing opposite effects that range from increasing cell viability to provoking cell death. Those divergent outcomes make the generalization of expected effects difficult for cell models not yet studied. This paper presents the effect of LIPUS on the viability of the MIO-M1 cell line for two well-established setups and different protocols; the acoustic intensities, duty factors, and treatment duration were varied. Measurements and models for acoustic and thermal analysis are included for proposing a solution to improve the reproducibility of this kind of experiments. Results indicate that MIO-M1 viability is less affected for the cells treated through a dish that is partially immersed in water; in these conditions, the cells neither show detrimental nor proliferative effects at intensities lower than 0.4 W/cm2 at 20% duty factor. However, cell viability was reduced when LIPUS was followed by cell subculturing. Treating the cells through a gel, with the culture dish placed on the transducer, increases cell mortality by the production of standing waves and mixed vibration-acoustical effects. Using the water-based setup with a 1° dish inclination reduces the effects of standing waves.

An Emerging Target in the Battle against Osteoarthritis: Macrophage Polarization

Osteoarthritis (OA) is one of the most prevalent chronic joint diseases worldwide, which causes a series of problems, such as joint pain, muscle atrophy, and joint deformities. Benefiting from some advances in the clinical treatment of OA, the quality of life of OA patients has been improved. However, the clinical need for more effective treatments for OA is still very urgent. Increasing findings show that macrophages are a critical breakthrough in OA therapy. Stimulated by different factors, macrophages are differentiated into two phenotypes: the pro-inflammatory M1 type and anti-inflammatory M2 type. In this study, various therapeutic reagents for macrophage-dependent OA treatment are summarized, including physical stimuli, chemical compounds, and biological molecules. Subsequently, the mechanisms of action of various approaches to modulating macrophages are discussed, and the signaling pathways underlying these treatments are interpreted. The NF-κB signaling pathway plays a vital role in the occurrence and development of macrophage-mediated OA, as NF-κB signaling pathway agonists promote the occurrence of OA, whereas NF-κB inhibitors ameliorate OA. Besides, several signaling pathways are also involved in the process of OA, including the JNK, Akt, MAPK, STAT6, Wnt/β-catenin, and mTOR pathways. In summary, macrophage polarization is a critical node in regulating the inflammatory response of OA. Reagents targeting the polarization of macrophages can effectively inhibit inflammation in the joints, which finally relieves OA symptoms. Our work lays the foundation for the development of macrophage-targeted therapeutic molecules and helps to elucidate the role of macrophages in OA.